Revealing the structural complexity of ETS-10 using 4D-STEM & electron ptychography

Atomic-level structural elucidation of zeolites remains challenging, particularly due to their sensitivity to the electron beam, as in the case of ETS-10, which features a unique 12-membered ring titanosilicate framework with linear Ti–O–Ti chains. In this study, we demonstrate the use of four-dimensional scanning transmission electron microscopy (4D-STEM) combined with electron ptychography to image Eu-exchanged ETS-10 (Eu-ETS-10) at sub-angstrom resolution. A homemade ptychographic reconstruction algorithm based on the extended ptychographical iterative engine (ePIE) was developed, enabling recovery of high-fidelity phase contrast images. The reconstructed images reveal not only all T-sites, including Si and Ti atoms, but also light elements such as oxygen and extraframework Eu 3+ cations. Surface terminations and stacking faults were clearly resolved, allowing identification of the ABA and ABC polymorphs and their local transformations along the three dimensions through multislice reconstruction. These results validate ptychography as a powerful technique for atomic-scale analysis of fragile zeolitic materials offering unique insights into the structural complexity of ETS-10. • The structure of ETS-10 has been investigated. • Sub-angstrom resolution has been accomplished via electron ptychography • The three-dimensional structure have been elucidated • Surface termination can be accurately identified.